As a result of SBIR Phase I funding (*l R43 HL40770-01), Athens Research and Technology, Inc. (ART) has developed a prototype qualitative chromophoric assay that measures the functional levels of levels of alpha-1-proteinase inhibitor (A1PI, also known as alpha-1-antitrypsin) in plasma or serum. This assay, which ART refers to as PI Diagnostic, is a rapid and simple visual test to for determining individuals that have a genetic deficiency in alpha-1-proteinase inhibitor. In its present form, the assay is performed on plasma and does not require instrumentation to determine functional level. In this Phase II proposal, ART plans to modify PI Diagnostic with respect to sample material to be used in the assay and assay substrate. After respect to sample material to be used in the assay and assay substrate. After respect to sample material to be used in the assay and assay substrate. After optimizing the parameters, ART will perform efficacy tests to determine the reliability and accuracy of PI Diagnostic in detecting individuals with A1PI deficiency. The ultimate goal is to develop an assay that will be inexpensive and convenient to use in a variety of laboratory settings (newborn screening, reference, hospital laboratories and/or physicians's office) and for alternate site testing.